Book: Dirt – the erosion of civilisations

Dirt – the erosion of civilisations.
David. R. Montgomery. University of California Press.

This book is American thus the dirt in the title, the English equivalent would be “soil”. This makes the case that the history of many major civilisations has in fact been the history of their topsoil. Thus tribes grow in numbers on fertile flood plains then invade neighbouring tribes. A city system then grows and expands with increasing food harvests whilst no one notices the slow loss of topsoil. Pressure of population needs means that marginal land on hillsides is moved into food production. This works well for a time but steep slopes once ploughed are quickly denuded of friable earth leaving bedrock. At this point of maximal growth the civilisation collapses if it has no new territories to plunder. This mechanism is plotted through Greece, Roman, Mayan and Easter Island cultures.
Now the same scenario faces western civilisation. We have depended on the rich grain baskets of the Ukraine and Midwestern American states with their deep post glacial loam. This is eroding and losing depth. In England the same is seen in East Anglia where soil is blown away. So peak soil also threatens the collapse of a complex society, alongside peak oil.
Finally the book offers a solution of enriching the soil. The incorporation of all human waste back into the field ecosystems may cause some to squirm but it would be natural. Topsoil must be looked after and valued as the Soil Association maintains. A sustainable future within environmental limits extends to our relationship with the earth, literally.